BACKGROUND: The objective of the current study was to determine the influence of media information on the opinions and feelings of patients with cancer and to measure the factors that affected the decision-making process and physician-patient communication. METHODS: The study consisted of a sequence of 2 nationwide surveys across the same dynamic target population of 2600 unselected patients with cancer who attended 1 of 13 centers throughout Italy. The authors measured the changes in patients' opinions and attitudes at the peak of a media campaign promoting the Di Bella therapy, an unproven cancer treatment method, and after the publicized demonstration of its ineffectiveness. An identical 10-item questionnaire was used. RESULTS: Opinions and feelings changed in the two surveys according to the way the media described the efficacy of the treatment, but physician-patient communication and the decision-making process remained unchanged. Multivariate analysis confirmed the enormous influence of the media on patient opinions (odds ratio [OR], 4.67; P < 0.0001), feelings of hope (OR, 3.63; P < 0.0001), and confusion (OR, 0.51; P < 0.0001), but not on physician-patient communication or the decision-making process. Educational level influenced almost all of the studied factors, and communication and decision-making also were influenced by the patients' gender and place of residence. There was no significant correlation with patient age. CONCLUSIONS: The media play a powerful role in affecting patients' opinions and feelings; the physician-patient communication and the decision-making process are not subject to media influence but are related primarily to level of education. The power of the media should be directed toward improving the spread of scientific knowledge to encourage behavioral changes, particularly among individuals with lower levels of education.